/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode() : val(0), next(nullptr) {}
 *     ListNode(int x) : val(x), next(nullptr) {}
 *     ListNode(int x, ListNode *next) : val(x), next(next) {}
 * };
 */
class Solution {
public:
    ListNode* reverseList(ListNode* head) {
        ListNode* newHead = new ListNode(0, nullptr);
        
        while(head != nullptr){
            ListNode* temp = head->next;
            head->next = newHead->next;
            newHead->next = head;

            head = temp;
        }

        return newHead->next;
    }
};